Add button facebook Instant games

Add button facebook Instant games

Hello, I'm developing a game for the facebook instant games platform and I need to add a preloader in theusing the API.I did everything correctly, but I'm having trouble addingthe blue "play now" button (Image: https://imgur.com/a/YmggUIP ) to make the game start only afterthe user clicks this video button: https: //youtu.be/Sjj_UKX549A

Anyone who knows the facebook api could tell me the correct way to add this button?